R5 "check oil level" allert

Anyone familiar with the R5 engine oil stick / sensor system? What happens now is the yellow check oil level-sign shows out randomly even though the engine oil level is normal, and when you take the stick out and put it back this will stop the yellow allert sign for another 70-150 km. The engine oli was changed about 500km ago and no sign about weird oil consumption or anything special.
How does the computer know I have checked the oil level? Some sensors build in the stick or what? The car is Touareg R5 2006 with 273000 km.